Timing a mating by the calendar is guesswork — progesterone tells you when ovulation actually happens.
The fertile window varies hugely between bitches and even between seasons, so counting days from the first bleeding is unreliable. Progesterone blood tests track the hormone rise that pinpoints ovulation and the best days to mate or inseminate.
Testing usually starts a few days into the season and repeats every couple of days. Progesterone stays low, then rises sharply around the luteinizing-hormone surge; ovulation follows, and the eggs need about two days to mature before they can be fertilized.
Your vet interprets the rising values to advise mating days — especially important with chilled or frozen semen, or when traveling to a stud. Log every value and date in the app so the pattern helps plan future seasons.
The full article library — and much more — lives in the DogCompanion app.
Download on the App Store